A reactor pressure vessel (RPV) of a boiling water reactor (BWR) typically has a generally cylindrical shape and is closed at both ends, e.g., by a bottom head and a removable top head. A core shroud, or shroud, typically surrounds the core and is supported by a shroud support structure.
Boiling water reactors have numerous piping systems, and such piping systems are utilized, for example, to transport water throughout the RPV. For example, core spray piping is used to deliver water from outside the RPV to core spargers inside the RPV and to cool the core. Typically, core spray piping is coupled between a nozzle in the RPV and a shroud connection in the shroud.
Stress corrosion cracking (SCC) is a known phenomenon occurring in reactor components, such as structural members, piping, fasteners, and welds, exposed to high temperature water. The reactor components are subject to a variety of stresses associated with, e.g., differences in thermal expansion, the operating pressure needed for the containment of the reactor cooling water, and other sources such as residual stresses from welding, cold working and other inhomogeneous metal treatments. In addition, water chemistry, welding, heat treatment and radiation can increase the susceptibility of metal in a component to SCC.
Reactor internal piping, such as core spray lines inside the reactor pressure vessel, occasionally require replacement as a result of SCC. One known method of replacing a core spray line requires draining the RPV and taking field measurements of the precise distance, e.g., horizontal and vertical, between the nozzle and the shroud connection. A replacement core spray line is then cut utilizing the measurements, and such replacement line is then welded in place. Replacing a core spray line typically requires considerable down time, and is tedious.
It would be desirable to provide an assembly which facilitates replacing a core spray line without requiring detailed field measurements and cutting. It also be desirable to provide such an assembly which would enable a core spray line to be replaced without requiring any welding.